Peyronie's disease (PD) and Dupuytren's contracture (DC) are fibrocontractive diseases of unknown etiology. In this proposal we outline an experimental plan designed to investigate the cell biological and immunological basis of these diseases. Cell cultures derived from PD plaque and DC nodule will be examined for morphological, biochemical, immunological, and functional characteristics that distinguish them from cultured cells derived from normal and control tissue explants. Since myofibroblasts have been implicated as one cell type in the fibrosis and contracture of PD and DC in vivo, cell lines will be examined for a) structural characteristics of myofibroblasts by transmission electron microscopy, b) chromosome number and structure by the quinacrine fluorescent banding technique, c) smooth muscle antigens of myofibroblasts by indirect immunofluorecence and d) the biosynthesis of type I and type III procollagens. Radiolabeled cell extracts of the cell lines will be analyzed by one- and two-dimensional gel electrophoresis for cellular polypeptide composition in an effort to identify cellular protein(s) that may be characteristic of, or responsible for, the fibromatosis. A possible autoimmune basis for PD and DC will be explored by a) investigating a possible immunogenetic association between particular histocompatibility (HLA) antigens and PD and/or DC and b) examining PD and DC patient sera and lymphocytes for evidence of humoral and/or cell-mediated autoimmune reactivity.